Reverse-current relay.



E. E. WEDMOEE E W. P. EAMLY-N.

REVERSE CURRENT RELAY.

APPLIGATIOIFILBD JUYHE 1908.

@atenten-'May e', 1913.

2 SHEETS-SHEET 2.

.FDA/:Um Il. IVE-MURE. WILLIAM P. EILMLYH.-

E m m sans? lTeenies To @all toit-om t may concern f Be it known that We, EDMUND B. Tlfno-- 'MORE and VILLIAM P. HAMLYN, subjects ot' switch upon the occurrence of reverse energy the King of Great Britain, residing at Rugby, England, have invented certain neviT and useful' Improvements in Revei.se-Ciiru rent Relays, of which the .following i'T a specication.

Our invention relates to protective4 devices for automatically opening electric circuits on the occurrence of reverse energy flow, and particularly .to devices of this type comprising a series and a potential coil differentially Wound and coperating' to. trip the circuit-breaker' or automatic flow,` and also 'arranged to operate on overload.l

In many cases it is desirable to' have a protective device which will open the cir' cuit automatically upon the occurrence of av'ery slight reverse energy flow, but which is not affected by an overload. In the ditferential lcoilprotective devices heretofore used diiculty is encountered because.. on severe overloads Without `any reverse energy flow the series coil overpov/vers the potential coil and causes the device to operate, while duringV a short circuit the voltagel drops and the sensitiveness ot the device to reverse' energy flow is very greatly reduced, on account of the seriesv coil overpowering the weakened potential coil. It is also desirable .na protective ldevice whichy wil respond inst'antl-y to a "very slightj reverse energy flow,

which is not altered i Ain 'sensitiveness' f iby la heavy currenti-tliro'ugliA the sriescoil, and- Which When coiistructed to fopen on "overload b'ra'tedto*changethelresponsiveness' to over?v toad 'Without afectingf 'the'jsens'itiveness tof reverse @energy lliow. W 1

In carrying out our invention We provide fa series i and afipotentialt coil" differentially -Wound and connected in. the usual way and veneers@ f specificati@ of Leiters Patent.

' ings, which are merely illustrative ot'- oiie `of Application ledJunc 6, 1908. Serial No. 437,172.

having a tripping armatureariangedtofv open the circuit-breaker orl yantoiiniitic.Sivit-cli"f when the relation of tlied'cii'ijre'iits' thronpli" Y the two coils changes en acco'unt ot-revei i energy ioiv. The tripping:fai-matureV is', 60 shielded from the influence ofv anffabiiorinalf current through the series coil by sonic p`i i` tective means which, is actuated tlieA ab normal current to complete magnetic cir'- cuit of low reluctance aroiind'- tlie tripping armature, thereby shunting the magnetic luX due to the abnormal current in" tl ie series coil past the tripping armature @and shielding it from said flux..l The means for sliunting a portion of thel magnetic fluxj' -from the tripping armature "ii'iay' assiim`e f variousforms, but is preterably'made inV the form of a movable armature, such -as tliecore commonly used with tripping coils, arranged to respond to,"`abnorinal"current through the overload coil-andestablish a closed path of iron for'thf'lu'x ofthe' series coil. The-deviceis prefeablyrendered 'responsive to overload by onne'ctingfthe means for shunting theft' ipping. arn'ia-ture `80 to the latch of the vcircuit reaker,'i v'liereby an overload`through .the4 eriescoil ivhich` causes the magnetic shunt-to b econie op- 'eratiye likewise trips the circuit-breaker and opens the circuit. Since tliejtgripping arma v81S ture responds only to reverse" currentfloiv and the means -for sliunting die-tripping armature. responds only -t`o"overload, and'.

'each may be calibrated independently ofv the 0ther,lthe sensitifeiiess ofthe device to l90 overload and to reverse energy V"flow may varied in any desired manner. j Our invention will best,beunderstoodin connection with the accompanying 'draivv the4 nianv forms in which the invention may be embodied, and in Wliichf#v FigureA l is an elevation Softhe magnetic circuit with the 'cor/e of thepot'ential coil 'l' ralngedfto 'respondfto overload asV ivell as to vings,theseries coil lend the potential coil' l 2 haven common' magnetic circuit comprising iron plates or yokes '3 anda' heldinll f-l whichy is threaded into the tube and Ainto theyoke '4; Since the tripping armature 8 is 1 included in the common magnetic -circuit of the 'two coils a denite amount vof magnetic flux, due either to the series coil 1-5 alone `or to the combined effect of both c'oils,'will cause the armature to rise into engagement with the fixed pole piece or core 7 and actuate a tripping pin 10 slidably mountedv inthe stationary pole lpiece 7 in a *2.0 posit-ion to be engaged by the tripping armature. The tripping pln may @pen the circuit in; any desired manner, either by en- 'gaging the latch of a circuit-breaker or by closing the circuit of the trip coil of an automatic switch;A

The device so far described constitutes a reverse current relay ofthe ordinary type, and the effect of abnormal current through the series coil of the tripping armature 8 is avoided by providing means for establishing a magnetic path of low reluctance between the yokes and 4 when the current through the series coil exceeds a predetermined limit, thereby causing the magnetic iux of the reluctance instead of through the tripping arma-ture.` Various forms of ma etic shunt may be used but the preferred orm is that shown in the drawings, in which atube 11 connects the two yokes and carries at the upper end a stationary pole piece, or core 12 with 'which coperates a movable 4core or shunting armature 13 slidably mounted 'iny the tube and extending through the yoke 4. 45. W'henjthe lpole piece 12 and the shunting armature 13 are in engagement the greater portion of the' -flux due to the series coil passes through them, and is thereby shunted from the tripping armature 8. The parts are so proportioned that under normal conditins the shunting armature 13 is in the position shown in Fig. `1 while upon the .occurrence of an abnormal current in the series coil, the shunting armature moves into engagement with the pole piece "l2, thereby shielding thetripping armature and preventing the opening of the circuit due to overload.'

If itis desired to provide a device which will vopen on overload as well as on reverse energy fiow, the shunting armature is made an overload armature by providing the pole 'piece-12 with a tripping pin 14 which opens the circuit in any/"suitable way, preferably 65 through the .tripping pin v10, to which it is series coil to pass through the path of'low connected by any suitable interlock, such as the bar 15. The shunting armature 13 is provided with a Calibrating stop 16 to varyl the amount of overloadrequired to actuate. it. The operation of this form4 of the'de- 71 vice is substantially the same as that shown .in `Fig. 1 except that the movement 0f the shunting armature 13,v due to overload on the. series coil, causes the circuit 'to be opened.4 Since the position ,of theshunting 7 armature 13 with relation to the core 12 may bevaried independently of armature 8 and core 7, the devlce canv be calibrated forany desired overload without in -any way aifecting its sensitiveness in responding to reverse 8( energy flow.

Our invention may be embodied in man other forms than "that shown and describe and we therefore do not wish to be restricted to thev exact form shown but intend to cover by the appended claims al1 changes and modifications ywithin the spirita-nd scope of our invention. l/Vhat we claim as new and desire to secure by Letters Patent of the United States, is

' l. In a protective device for electric cir,-

. cuits, the cpmbination withtwo coils and a trippingl armahire movable intov tripping posltion in response to the magnetic flux of said coils, of means responsive .to abnormal magnetic flux from one of said `coils for s'hunting .part of the flux from said trippin armature to prevent the tripping of -sai armature thereby.

2. In a protective device for electric circuits, t-he combination with a potential coil and a series ,coil differentially wound with g respect to each other inthe normal operation of the system, a tripping armature movable into tripping positionin response to a combined magnetic flu-X of both of said coils, and means responsiveto abnormal current in said series coil for shunting part of the magnetic flux'from said tripping armature.

3. In a protective device ffor electric-.cir- 1p cuits, the combination with differentially wound potential and series coils having a common magnetic circuit and 4a tripping armature forming part of said magnetic. circuit, of a shunting armature actuated by 115 said series coil to divert part ofthe magnetic flux of said series `coil from said tripping armature.

l4. In a protective devicefor electric cir- 'cuits,' the combination with diiferentially 120 wound series and potential coils having a "v common magnetic circuit, of a movable' core 4 for said potential coil forming part of said magnetic circuit, and an armature actuated by abnormal current in saidseries coilto complete a magnetic circuit of low vreluctance independent of said core, thereby shunting part of the magnetic flux from said core z f 5. In a protective device for electric cir- 130 cuits` the combination with differentially Wound coils haring a common magnetic circuit, of two armatures forming part of said magnetic circuit, one arranged to shunt part of the magnetic flux ot' said circuit. from the other, and means'actuated b v either of said armatures to open the eircuitto he proteeted.

6. In a protective device for electric c`rcuits, the combination with differentially Wound series .and potential coils having a common magnetic flux, of two independent armatures,responsive to the magnetic flux in'said magneticl circuit and one arranged to shunt said flux from thil other, means for 15 adjusting eacharmature indepeiidently of the other, and means actuated by either of said armatures to open the circuit to be pro tected.

In witness whereof, we have hereunto set 20 our hands this 25th day of May, 1908.

EDMUND B. VEDMORE. VILLIAM P. HAMLYN.

Titnesses v CHARLES H. FULLER, J. A. FOSTER. 

